This invention relates to display boards such as boards of the type used by electrical power companies to display representations of power lines and switches on a map of a region. Prior art display boards of this particular type have been relatively expensive, difficult to update, or of poor graphic quality.
One prior art system utilizes plastic squares or tiles that are mechanically snapped into special frames to form a graphic mosaic. These tiles are typically 1" square. Standard graphics and symbols are applied to each square by etching, silk screening or other convenient technique, and the tiles are selected and assembled to form the desired image. Thousands of such tiles are required in a typical display board. Thus the board is generally used to depict transmission or distribution systems in a schematic format rather than a geographic format, which requires a resolution not easily achieved by such tiles. Typical examples of such boards are disclosed in Navalle U.S. Pat. No. 2,804,607 and in Canadian Patent No. 770,860. A prior art mosaic tile display board portraying a geographical background is disclosed in Neuberger U.S. Pat. No. 4,505,061.
Another prior art display board used for representing electrical power distribution systems comprises a steel peg board painted to represent a geographical background. Power distribution equipment is represented by applying pieces and strips of tape to the painted board.
An improved display board is disclosed in copending, commonly owned U.S. patent application Ser. No. 07/316,120 filed Feb. 24, 1989 and incorporated herein by reference. That display board uses a matrix of rectangular modules, each comprising a flexible steel base plate imprinted on one side by a pattern of graphics. Magnetic rubber sheet material is used for releasably mounting the modules on a support board. When the modules are assembled upon the support board in their proper arrangement, their printed patterns cooperatively display a regional image. Printing is accomplished by silk screening or by computer driven plotting. The present application relates to a method of accomplishing such plotting.